What's under your seat?

As the Lyday family headed through Raleigh Durham International Airport for their summer vacation recently, they knew they would have to go through security screening and that their checked baggage would get x-rayed.

But until ABC11 told them, they did not know that there's no requirement for all cargo to be screened before it gets loaded on passenger planes.

"That's a little scary, offered Suzanne Lyday. "It does surprise me that all of the cargo is not screened that goes on the plane."

Three years ago, Congress passed the 911 Commission Act which requires all cargo on passenger planes to be screened by August 1, 2010.

Right now, a quarter of all cargo is not screened. And 10 days before the deadline to reach the 100 percent, a government watchdog agency is warning that may not happen.

Just last month, the Government Accountability Office released a report that says:

"The security threat posed by terrorists introducing explosive devices in air cargo shipments is significant, and the risk and likelihood of such an attack directed at passenger aircraft is high."

The GAO also warned lawmakers at a recent congressional hearing about the deadline.

"The TSA faces several challenges in developing and implementing a system to screen 100 percent of domestic air cargo and it is questionable based on reported screening rates, whether 100 percent of such cargo will be screened by August 2010," the GAO's Stephen Lord told lawmakers.

American Airlines granted ABC11 security clearance inside its global headquarters at the Dallas - Fort Worth airport to show us how it's preparing for the deadline.

"You know what? I'm not nervous," he responded. "We have been working on this for 3 years, okay? As I mentioned we've been stepping up the amount of screening that we're doing, so we're not too far away of being at 100 percent."

Brooks is the man in charge of the entire global cargo operation at American. It's a complex operation to handle all the cargo that needs to get places quickly.

While we were there, ABC11 cameras recorded live boas and pythons headed for France, fresh seafood headed to Sushi bars around the world, fresh flowers coming in from Columbia, and vaccine headed out to Argentina.

750,000 pounds of cargo moves through the Dallas - Fort Worth facility on a busy day.

"Have you had sleepless nights over the years about the stuff that's shipped on your planes?" asked Daniels.

"I haven't had many," said Brooks. "All it will take is one bad day and we could be out of business. So, that's a tremendous motivator."

Brooks says American is spending $10 million preparing for the August 1 screening deadline. Equipment like a huge new x-ray machine can screen an entire pallet of cargo in 15 seconds.

"A typical old x-ray machine was basically a single view. These dual views can actually give a top and side angle view, and you can actually zero in on one box in the middle," explained Keith May with American Airlines security.

The airline also has smaller x-ray machines to screen single boxes and explosive trace detection machines that sniff for explosive chemicals.

The government also has a program allowing certified shippers to pre-screen cargo and drop it off at the airport.

"You believe it's okay for people to show up here and say to you, 'We've screened this. It's safe to get on your airplane?'" asked Daniels.

"Our customers, for the most part, are the world's largest freight forwarders. They have everything at stake if they give us a shipment they can't stand by. So, if they're willing to sign up for a federally supervised screening program, that's good enough for me," said Brooks.

Across the country, 20 million pounds of cargo gets shipped on passenger planes every day. Brooks says the next time you fly you should feel safer.

"After August 1, everything that is under their seats that is an air cargo shipment … has been screened," he explained.

"The other thing that I think passengers can take comfort in is that there's a lot that happens behind the scenes that they don't see," he continued. "There are multiple layers of security above and beyond what we're doing."

Even though government investigators say the TSA is facing challenges in meeting the cargo screening deadline, passengers like Suzanne Lyday say they're relieved to know that is the goal.

"It will make me feel better, much better, to know that it's all screened," she said.

The Government Accountability Office is also concerned about cargo that arrives from foreign airports and is then put on domestic flights in the U.S.

It's also supposed to be screened by August 1, but the TSA says it may take years to comply with the law to screen 100 percent of that cargo.

ABC11 asked American Airlines about that. It says all cargo on all of its international flights will be screened by August 1.